Radioactivity Flashcards
What Are Alpha Particles Made Up Of?
2 protons and 2 neutrons (same as the nucleus of a helium atom)
What Is The Overall Charge Of An Alpha Particle?
2+
What stops alpha particles?
A sheet of paper or a human hand
How ionising are alpha particles?
Strongly ionising
What Are Beta Particles Made Up Of?
Fast moving electrons
What Is The Overall Charge Of A Beta Particle?
-1
What stops beta particles?
5mm of aluminium
How ionising are beta particles?
Moderately ionising
What are gamma rays?
Electromagnetic wave radiation released by the nucleus
What stops gamma rays?
Thick lead or concrete
What Happens During An Alpha Decay?
- Mass number loses 4 protons and neutrons
- Atomic mass number loses 2 protons
What Happens During A Beta Decay?
Mass stays the same and adds one to atomic number
What Happens During A Neutron Emission?
- Mass number decreases by 1
- Atomic number remains the same
What is the ‘Activity’ during Radioactive decay?
The overall rate of decay of all of the radioactive isotopes in our sample
What are the units of ‘Activity’?
Becquerels (Bq)
What is a half-life?
The time taken for the number of radioactive nuclei in an isotope to halve.
What device is used to record radioactive decays?
Geiger-Muller tube and counter
What is visible light?
The part of the electromagnetic spectrum that our eyes can detect
What are optical fibres?
Thin glass or plastic fibres that are used to transmit data really quickly over very large distances
What Are The Advantages Of Using Optical Fibres?
- Transmit much more information
- Signal is less likely to be distorted
What is fluorescence?
Ultraviolet light energy being absorbed and re-emitted as visible light
Properties Of Ultraviolet Radiation
- Shorter wavelength than visible light
Examples of Ultraviolet Waves
- The Sun ~ Sun Tan or Sun Burn
- Security Pens ~ Completely invisible until we shine UV Light
- Sterilise Water ~ Destroys Micro-organisms
What Are The Safety Precautions Of Radiation & Absorption Practical?
- Never direct radioactive sources towards someone
- Handle radioactive sources with tongs.
- Minimise the exposure time by only removing sources from their lead lined boxes when in use
